This is an incomplete Google Books scan of the 1961 pamphlet The Complete Checklist Of Science-Fiction Magazines by Bradford M. Day (1916-2004).
I say "incomplete" because the scan is lacking scans of pages 30 and 31 that the Google Books scanner apparently forgot to scan (the book jumps from magazines whose titles begin with the letter "J" to those with the letter "M").
And it may possibly be lacking two pages at the end. This copy ends with page 61 (with "Weird Tales") but online references call for 63 pages.
The Complete Checklist Of Science-Fiction Magazines is something of a curiosity among SF reference books, of interest today perhaps just for completists.
It's exactly what the title says it is - it's a literal checklist with tables with rows of little boxes on each page in which a collector could place a checkmark or dot to keep track of the issues of the SF magazines that they owned and be aware of the issues that they needed. It covers magazines up to December 1960.
I've included a scan at the end of the file that I found online that
shows how the book was supposed to be used. It's a scan of pages 10 and
11 of the book and shows how one collector had kept track of his
collection of Astounding Stories.
Day would go on to publish one more edition of the book in 1993: The Checklist Of Science-Fiction And Fantasy Magazines: 1892 — 1992.